[realtek-ambz2] Update base core to new structure

docs/dev/stdlib.md

@@ -0,0 +1,102 @@
+# C stdlib
+
+Usually, functions available in C standard library should not be defined by the SDK. Instead, they should be included using GCC's headers, and implemented by the libc or wrapped and implemented in the SDK.
+
+The following functions must not be defined by the SDK. Their presence makes conflicts due to incompatibility with C library, so they should be removed or disabled, and replaced with wrappers.
+
+Memory management functions should be wrapped and redirected to FreeRTOS (if possible).
+
+Additionally, if the `printf` library is used in the chip family code, all other vendor-defined printf-like functions should be replaced with it.
+
+Function prototypes taken from [devdocs.io](https://devdocs.io/c/).
+
+```cpp
+// stdlib.h / Dynamic memory management
+void *calloc(size_t num, size_t size);
+void *malloc(size_t size);
+void *realloc(void *ptr, size_t new_size);
+void free(void *ptr);
+// stdlib.h / Conversions to numeric formats
+double atof(const char *str);
+int atoi(const char *str);
+long atol(const char *str);
+long long atoll(const char *str);
+double strtod(const char *str, char **str_end);
+float strtof(const char *str, char **str_end);
+long strtol(const char *str, char **str_end, int base);
+long double strtold(const char *str, char **str_end);
+long long strtoll(const char *str, char **str_end, int base);
+unsigned long strtoul(const char *str, char **str_end, int base);
+unsigned long long strtoull(const char *str, char **str_end, int base);
+
+// string.h / Character classification
+int isalnum(int ch);
+int isalpha(int ch);
+int islower(int ch);
+int isupper(int ch);
+int isdigit(int ch);
+int isxdigit(int ch);
+int iscntrl(int ch);
+int isgraph(int ch);
+int isspace(int ch);
+int isblank(int ch);
+int isprint(int ch);
+int ispunct(int ch);
+int tolower(int ch);
+int toupper(int ch);
+// string.h / String manipulation
+char *strcat(char *dest, const char *src);
+char *strcpy(char *dest, const char *src);
+char *strncat(char *dest, const char *src, size_t count);
+char *strncpy(char *dest, const char *src, size_t count);
+size_t strxfrm(char *dest, const char *src, size_t count);
+// string.h / String examination
+char *strchr(const char *str, int ch);
+int strcmp(const char *lhs, const char *rhs);
+size_t strcspn(const char *dest, const char *src);
+size_t strlen(const char *str);
+int strncmp(const char *lhs, const char *rhs, size_t count);
+char *strpbrk(const char *dest, const char *breakset);
+char *strrchr(const char *str, int ch);
+size_t strspn(const char *dest, const char *src);
+char *strstr(const char *str, const char *substr);
+char *strtok(char *str, const char *delim);
+// string.h / Character array manipulation
+void *memchr(const void *ptr, int ch, size_t count);
+int memcmp(const void *lhs, const void *rhs, size_t count);
+void *memcpy(void *dest, const void *src, size_t count);
+void *memmove(void *dest, const void *src, size_t count);
+void *memset(void *dest, int ch, size_t count);
+
+// stdio.h / Unformatted input/output
+int putc(int ch, FILE *stream);
+int putchar(int ch);
+int puts(const char *str);
+
+// stdio.h / Formatted input/output
+int printf(const char *format, ...);
+int sprintf(char *buffer, const char *format, ...);
+int snprintf(char *buffer, size_t bufsz, const char *format, ...);
+int vprintf(const char *format, va_list vlist);
+int vsprintf(char *buffer, const char *format, va_list vlist);
+int vsnprintf(char *buffer, size_t bufsz, const char *format, va_list vlist);
+
+// Non-stdlib
+_calloc_r
+_free_r
+_malloc_r
+_realloc_r
+atoui
+atoul
+atoull
+strlcpy
+strnicmp
+strnlen
+strsep
+zalloc
+
+// Additional forbidden macros
+#define max(a, b)
+#define min(a, b)
+typedef bool boolean;
+```